Running PopOS on a 2012 Macbook Air and Fedora on a 2015 Macbook Pro.
Potential common pitfall used to be having to add the Broadcom wifi drivers separately - I had to add them manually for PopOS but Fedora worked out of the box. Honestly PopOS + Wayland totally saved the old little Air and it’s a fantastic machine to use.
You may have to start using some free third-party tools for built-in features that work on the Mac.
I replaced iCloud keychain with BitWarden for password management. You can use Beeper for iMessage - it’s one of the few things to actually support it. iCloud Drive can be accessed via rclone I think but it might be terminal only - mind if you can get it to work via terminal then you can mount it as a folder. You can use Cider as an Apple Music client. I haven’t yet looked into Calendar and Contacts sync with iCloud but you can always export those and import in your software of choice on Linux.